%{

#include <stdio.h>
void rule_number( int );

extern int yylex(void);
extern int yyerror(char *);

%}

%token ID

%%

start : expr '#'		{ rule_number( 1 ); YYACCEPT; }
      ;

expr  : term			{ rule_number( 2 ); }
      | expr '+' term		{ rule_number( 3 ); }
      | expr '-' term		{ rule_number( 4 ); }
      ;

term  : ID			{ rule_number( 5 ); }
      | '(' expr ')'		{ rule_number( 6 ); }
      ;

%%

int main()
{
  fprintf( stderr, "Enter your expression:\n" ); 
  yyparse();

  return 0;
}

void rule_number( int n )
{
  fprintf( stdout, "Rule number %2d\n", n );
}

int yyerror( char *s )
{
  fprintf( stderr, "--%s--\n", s );

  return 0;
}